A method of performing a reconstruction of data in a redundant array of independent disks (RAID) system with a protection pool of storage units includes receiving a request to perform a reconstruction of a first set of physical extents stored on a first physical disk of a set of physical disks. Each physical extent of the first set of physical extents is associated with an array of a second set of physical extents. The second set of physical extents is distributed across the set of physical disks. The method further includes allocating a third set of physical extents on one or more physical disks of the set of physical disks other than the first physical disk, and distributing data from each of the first set of physical extents of the first physical disk to a corresponding physical extent of the third set of physical extents.

Techniques for disk failure control involve determining the number of failed disks in a Redundant Array of Independent Disks (RAID). The techniques further involve comparing the number of failed disks with a predetermined threshold; and in accordance with a determination that the number of failed disks exceeds the predetermined threshold, setting at least one non-failing disk in the RAID into a protection mode to prevent the at least one non-failing disk from being disconnected. Such techniques facilitate prevention of the user data loss in the RAID.

Techniques involve determining whether data read from a redundant array of independent disks (RAID) is corrupted, the RAID including two parity disks. The techniques further involve determining, based on the read data being corrupted, whether single-disk data recovery can recover the corrupted data. The techniques further involve recovering, based on the single-disk data recovery failing to recover the corrupted data, the corrupted data using dual-disk data recovery. Such techniques may present a recovery solution for silent data corruption of a RAID with two parity disks, such that corrupted data can be recovered in the case of either a single-disk failure or a dual-disk failure, thereby improving the storage system performance.

A method for use by a source storage unit of a dispersed storage network includes identifying a slice name corresponding to a slice to migrate from a source storage unit to a destination storage unit; sending the slice to migrate to the destination storage unit; generating a slice verification request and sending the slice verification request to the destination storage unit; receiving an integrity value from the destination storage unit; and determining when the integrity value compares favorably to the slice verification request. When the source storage unit determines that the integrity value compares favorably to the slice verification request, a slice name assignment associated with the slice name is updated and the slice is deleted from the source storage unit.

Embodiments of the present invention provide systems and methods for recovering a high availability storage system. The storage system includes a first layer and a second layer, each layer including a controller board, a router board, and storage elements. When a component of a layer fails, the storage system continues to function in the presence of a single failure of any component, up to two storage element failures in either layer, or a single power supply failure. While a component is down, the storage system will run in a degraded mode. The passive zone is not serving input/output requests, but is continuously updating its state in dynamic random access memory to enable failover within a short period of time using the layer that is fully operational. When the issue with the failed zone is corrected, a failback procedure brings the system back to a normal operating state.

A method of operating a storage device may include determining a fault condition of the storage device, selecting a fault resilient mode based on the fault condition of the storage device, and operating the storage device in the selected fault resilient mode. The selected fault resilient mode may include one of a power cycle mode, a reformat mode, a reduced capacity read-only mode, a reduced capacity mode, a reduced performance mode, a read-only mode, a partial read-only mode, a temporary read-only mode, a temporary partial read-only mode, or a vulnerable mode. The storage device may be configured to perform a namespace capacity management command received from the host. The namespace capacity management command may include a resize subcommand and/or a zero-size namespace subcommand. The storage device may report the selected fault resilient mode to a host.

Reconfiguring a storage system based on resource availability, including: limiting a number of storage devices in a storage system that may be simultaneously servicing write operations; determining that an amount of required write bandwidth has changed; and subsequent to determining that the amount of required write bandwidth has changed, adjusting, by a computer processor, the number of storage devices in the storage system that may be simultaneously servicing write operations.

A method and system for managing a storage system, the method comprising: creating a storage system including a first number of stripes, wherein each of the first number of stripes includes a second number of extents, and each of the second number of extents is distributed over a different storage device in a group of storage devices; with respect to a stripe among the first number of stripes, generating stripe information descriptive of a mapping relation between the second number of extents included in the stripe and the different storage devices in the group of storage devices; and with respect to a storage device where an extent among the second number of extents is located, building extent information about a mapping relation between an extent in the storage device and the stripe. In one embodiment of the present invention, there is provided a corresponding device and system.

A technique involves: in response to establishing a stripe in a Redundant Array of Independent Disks (RAID), generating first mapping information of the stripe in a block allocated for the stripe, the RAID being built based on extents obtained by dividing disks, the stripe including a first extent set, the first mapping information recording respective disk locations of the first extent set; in response to a failure occurring in a first disk where a first extent in the first extent set is located, replacing the first extent with a second extent to obtain a second extent set corresponding to the stripe; generating second mapping information of the stripe in the block, to record respective disk locations of the second extent set; and in response to the first disk being recovered from the failure, restoring data in the stripe based on the first mapping information and the second mapping information.

Techniques for accessing data involve reading data from at least one disk among a plurality of disks. Such techniques further involve detecting whether a lookup table stored on a memory is empty, where the lookup table stores information indicating data loss. Such techniques further involve comparing, in response to the lookup table not being empty, data read information associated with the read data with table items in the lookup table to determine whether there is a table item in the lookup table that matches the data read information. Such techniques further involve sending, in response to determining that there is a table item that matches the data read information, the information indicating data loss. Such a technique improve the efficiency of data access, reduces the complexity of the system and the power consumption of the system, and improves the performance of the system.